In Vitro Susceptibility of Nonfermenting Gram-Negative Rods To Meropenem–Vaborbactam and Delafloxacin

Abstract

Aim: Meropenem–vaborbactam and delafloxacin activities were not assessed against Achromobacter spp. (Achr), Burkholderia cepacia complex (Bcc) and Stenotrophomonas maltophilia (Smal). Methodology: A total of 106 Achr, 57 Bcc and 100 Smal were tested with gradient diffusion test of meropenem–vaborbactam, delafloxacin and comparators. Results: Meropenem–vaborbactam MIC₅₀ were 4 μg/ml for Achr, 1 μg/ml for B. cepacia, 2 μg/ml for B. cenocepacia and B. multivorans, and 32 μg/ml for Smal. Delafloxacin MIC₅₀ were 4 μg/ml for Achr, 0.25 μg/ml for B. cepacia and B. multivorans, 2 μg/ml for B. cenocepacia, and 0.5 μg/m for Smal. meropenem–vaborbactam MICs were fourfold lower than meropenem for 28.3% Achr, 77.2% B. cepacia, 53.8% B. cenocepacia and 77.2% B. multivorans. Conclusion: Meropenem–vaborbactam and delafloxacin are in vitro active against Bcc and Achr.

Plain language summary

We assess the efficacy of two new antibiotics, meropenem–vaborbactam and delafloxacin, to kill rarely encountered bacteria. These bacteria, Achromobacter, Burkholderia and Stenotrophomonas maltophilia, mainly cause respiratory tract infections. Both antibiotics are found active against Achromobacter and Burkholderia, but not S. maltophilia.

Tweetable abstract

Meropenem–vaborbactam (Vaborem^®) and delafloxacin (Quofenix^®) are active against most strains of Achromobacter and Burkholderia cepacia complex, but against not S. maltophilia

Keywords::

• Achromobacter
• Burkholderia
• cystic fibrosis
• delafloxacin
• lung transplant recipient
• meropenem
• Stenotrophomonas
• transplantation
• vaborbactam

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at: www.tandfonline.com/doi/suppl/10.2217/fmb-2021-0278

Author contributions

Conceptualization/methodology: E Farfour. Investigation: all authors. Writing – original draft: E Farfour. Writing – review and editing: all authors.

Acknowledgments

The authors are grateful of Menarini laboratories for providing meropenem–vaborbactam and delafloxacin strip test. The authors thank M Frayssinoux for performing antibiotic susceptibility testing.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.